Image transfer method

Abstract

In transferring a toner image carried on a toner image carrier onto a transfer medium, a uniform charge is imparted to the surface of the toner image carrier while a charge of the same polarity as the uniform charge is imparted to the surface of the transfer medium, whereafter a toner image is transferred from the surface of the toner image carrier to the surface of the transfer medium.

We claim: 
     
       1. An image transfer method for transferring a toner image from a surface of a toner image carrier onto a transfer medium, comprising the steps of: forming a toner image on said toner image carrier;   imparting a uniform charge of predetermined polarity to the surface of said toner image carrier carrying said toner image;   imparting a first uniform charge of the same said polarity to one surface of said transfer medium;   contacting said one surface of said transfer medium to said surface of the toner image carrier after imparting said charge to said transfer medium, and simultaneously maintaining the opposed surface of said transfer medium at a predetermined voltage during said contact, thereby transferring the toner image from said surface of said toner image carrier to said one surface of said transfer medium; and   subsequently separating the transfer medium from the image carrier.   
     
     
       2. An image transfer method according to claim 1, wherein the charge potential imparted to said surface of said transfer medium is set to a level below the charge potential on said surface of said toner image carrier. 
     
     
       3. An image transfer method according to claim 1, further comprising the step of imparting a charge to said transfer medium after image transfer, wherein said second charge has a polarity opposite to said first charge. 
     
     
       4. An image transfer method for transferring toner images successively formed on a toner image carrier onto a surface of a transfer medium in superposed relationship, comprising the steps of forming a color resolved toner image on the toner image carrier; imparting a uniform charge to the surface of said toner image carrier bearing said toner image; imparting a charge of the same polarity as that of said uniform charge to the surface of said transfer medium; contacting said transfer medium to said surface of the toner image carrier after imparting said charge to said transfer medium thereby transferring the toner image from said carrier to said transfer medium; and successively repeating a sequence of steps including forming a color resolved toner image on the toner image carrier, wherein each image is developed with a different color toner, imparting a uniform charge to the surface of the toner image carrier, and contacting said transfer medium to said surface of the toner image carrier, thereby transferring the successive different color images to the transfer medium. 
     
     
       5. An image transfer method method according to claim 4, wherein the charge potential imparted to said surface of said transfer medium is set to a level below the charge potential on said surface of said toner image carrier. 
     
     
       6. An image transfer method according to claim 4, wherein subsequent to the first image transfer but prior to the transfer of each of the other toner images, a charge of said same polarity is imparted to said surface of said transfer medium to a potential below the potential of the immediately previous charge.